Production method for unvulcanized rubber member and tire

ABSTRACT

A method of producing an uncured rubber member by separately producing a rubber composition A of a compounding system excluding a vulcanizing agent and a rubber composition B of a compounding system excluding a vulcanization accelerator and shaping the rubber compositions A and B into given forms through a shaping machine and winding on a rotating support does not cause the scorching at the shaping step and is high in the shaping efficiency. Also, the durability and the internal pressure holding property at a run-flat state are simultaneously established in a tire provided with an innerliner in which a rubber component for the innerliner contains at least 10% by mass of diene rubber in a region corresponding to a tire side portion and a ratio of diene rubber in a region corresponding to a tire tread portion is made lower than that in a side portion corresponding region.

TECHNICAL FIELD

This invention relates to a process and an apparatus for producing anuncured rubber member as well as a tire and a method of producing thesame, and more particularly to a process and an apparatus for producingan uncured rubber member in which two or more kinds of uncured rubbercompositions are separately extruded and wound on a rotating support aswell as a run-flat tire capable of safely running even if an airpressure of the tire drops and a method of producing the same.

BACKGROUND ART

In general, a composite having various rubbers is required to take sucha step that various uncured rubber members are stuck beforevulcanization in the production of the composite. When the composite isa pneumatic tire (hereinafter referred to as a tire), the tire iscomprised of reinforcing members such as organic fiber or steel cordsand various rubber members. Therefore, an uncured tire formed bysticking uncured rubber members and reinforcing members such as cordsand the like is provided at a shaping step before the vulcanization oftire.

At present, performances required for the rubber composites inclusive ofthe tires tend to be more upgraded and diversified. For this end, theshaping step becomes naturally complicated and it is actual state thatmanual operation is still required. However, as the manual operationgets into the shaping step, a big improvement of a shaping efficiencycan not be attained, and also there is a problem that a stickingaccuracy of various members lowers. In case of the tire, the improvementof the sticking accuracy is strongly demanded in addition to theimprovement of the shaping efficiency because the good or bad stickingaccuracy particularly controls the quality of the tire.

In order to meet the above demand, JP-B-7-94155 proposes a process andan apparatus wherein an outlet orifice of a constant delivery extruderis located in the vicinity of a position for arranging a rubber memberon a rotating support and a rubber composition is directly extruded fromthe constant delivery extruder through the outlet orifice onto thesupport. Also, JP-A-2000-79643 proposes a process and an apparatuswherein plural rubber compositions are directly extruded onto thesupport through a single extruding device with mixing.

In the extrusion methods described in the above publications, however,if the extrusion rate is made faster for increasing the shapingefficiency, there is a problem of largely fearing that the heat build-upof the rubber composition is caused by friction in the extruder to causescorching (phenomenon of causing vulcanization at an unanticipatedtime). On the contrary, if it is intended to reduce the friction in theextruder by making the extrusion rate slow, there is a problem oflowering the shaping efficiency. Therefore, these methods are not aneffective solution means.

Further, when the vulcanization rate is made slow by selecting the kindof vulcanization accelerator or by decreasing amounts of vulcanizingagent (sulfur) and vulcanization accelerator, the scorching hardlyoccurs, but there is a problem that it is required to prolong thevulcanization time.

On the other hand, the safety of the tire is put importance on, and as aresult, there are demanded run-flat tires capable of running even whenthe internal pressure is dropped due to foreign matters such as nail andthe like or any cause. In this connection, there are proposed theinsertion of a filler body or a core cylinder into an inside of thetire, the use of a side reinforcing rubber as described in JP-A-4-185512and so on.

As one drawback in the above side-reinforced type run-flat tire, thebending of the side portion in the running of the tire after the drop ofthe internal pressure becomes fairly large as compared with that in thepresence of the internal pressure and rubber peeling is caused betweenrubbers. Because, an innerliner is made of only butyl rubber or ahalogenated butyl rubber and the side reinforcing rubber is mainlycomposed of a diene-based rubber and hence an adhesion forcetherebetween is insufficient. There is a fear that the side reinforcingrubber is further broken accompanied with the rubber peeling to make therunning impossible.

When the innerliner is made of a diene rubber for preventing the rubberpeeling, since the diene rubber is low in the ability of preventing airpermeation, there is an unfavorable problem that air impermeabilityinherent to the innerliner lowers.

When the side reinforcing rubber is butyl rubber, the peeling is causedbetween the carcass ply and the side reinforcing rubber but also thedurability comes into problem because the heat build-up of the butylrubber is large.

When natural rubber is co-used in the innerliner composed mainly ofbutyl rubber or halogenated butyl rubber, the adhesion force to theother member made of diene-based rubber is improved, but there is aproblem that an internal pressure holding property largely lowers due tothe presence of the natural rubber being low in the ability ofpreventing air permeation because the innerliner is formed with asheet-like rubber having a single composition in the conventional drumshaping.

DISCLOSURE OF THE INVENTION

It is a first object of the invention to provide a process and anapparatus for producing an uncured rubber member without causing thescorching at a shaping step and in a high building efficiency.

It is a second object of the invention to provide a tire establishing adurability at a run-flat state and an internal pressure holding propertyand a method of producing the same.

Means for achieving the first object are as follows:

-   (1) A process for producing an uncured rubber member, which    comprises separately preparing a rubber composition A of a    compounding system excluding a vulcanizing agent and a rubber    composition B of a compounding system excluding a vulcanization    accelerator, and shaping the rubber composition A and the rubber    composition B into respective desired forms in a shaping machine to    wind on a rotating support.-   (2) A process for producing an uncured rubber member according to    the item (1), wherein said shaping machine is an extruder.-   (3) A process for producing an uncured rubber member according to    the item (1) or (2), wherein the form of the rubber composition A    and/or B after the shaping is any one of a sheet, a ribbon and a    string.-   (4) A process for producing an uncured rubber member according to    any one of the items (1) to (3), wherein the rubber composition A    and/or B after the shaping is helically wound.-   (5) A process for producing an uncured rubber member according to    any one of the items (1) to (4), wherein the rubber compositions A    and B are cooled before the winding on the rotating support.-   (6) A process for producing an uncured rubber member according to    any one of the items (1) to (5), wherein an existing ratio of the    rubber composition A to the rubber composition B in the uncured    rubber member is adequately changed.-   (7) A process for producing an uncured rubber member according to    any one of the items (1) to (5), wherein an existing ratio of the    rubber composition A to the rubber composition B in the uncured    rubber member is adequately changed in a widthwise direction of the    support.-   (8) An apparatus for producing an uncured rubber member comprising a    rotating support and plural extruders communicating with the    support.-   (9) An apparatus for producing an uncured rubber member according to    the item (8), which further comprises a cooling device between the    extruder and the support.

Means for achieving the second object are as follows.

-   (10) A tire provided with an innerliner, characterized in that a    rubber component in the innerliner contains at least 10% by mass of    a diene rubber in a portion corresponding to a side portion of the    tire and a ratio of the diene rubber is lower in a portion    corresponding to a tread portion of the tire than that in the    portion corresponding to the side portion.-   (11) A tire according to the item (10), wherein the rubber component    of the innerliner contains 10-40% by mass of the diene rubber in the    portion corresponding to the side portion of the tire.-   (12) A tire according to the item (10) or (11), wherein the rubber    component of the innerliner is composed mainly of a halogenated    butyl rubber and contains 90-60% by mass of the halogenated butyl    rubber and 10-40% by mass of the diene rubber.-   (13) A tire according to any one of the items (10) to (12), wherein    the diene rubber is natural rubber.-   (14) A tire according to any one of the items (10) to (13), wherein    a reinforcing rubber of substantially a crescent-shaped section is    arranged between an innerliner and a carcass ply in the side portion    of the tire.-   (15) A tire according to the item (10) or (11), wherein a ratio of    the diene rubber in the rubber component of the innerliner is    continuously changed in a region ranging from the portion    corresponding to the side portion of the tire to the portion    corresponding to the tread portion of the tire.-   (16) A method of producing a tire provided with an innerliner by    taking out different rubber compositions from plural storing tanks    each containing the respective rubber composition, extruding through    an extruder while kneading them and winding the resulting extrudate    on a rotating support to form an innerliner layer for the tire,    characterized in that take-out amounts of these rubber compositions    are changed so that a rubber component in the innerliner contains at    least 10% by mass of a diene rubber in a portion corresponding to a    side portion of the tire and a ratio of the diene rubber is lower in    a portion corresponding to a tread portion of the tire than that in    the portion corresponding to the side portion.-   (17) A method of producing a tire according to the item (16),    wherein the take-out amounts are continuously changed.-   (18) A method of producing a tire according to the item (16) or    (17), wherein the rotating support is a rigid core having an outer    face shape substantially corresponding to an inner face shape of a    product tire.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial section view illustrating a winding state of arubber composition in the production process of an uncured rubber memberaccording to the invention.

FIG. 2 is a schematic view of a production apparatus according to theinvention.

FIG. 3 is a schematically side view of an apparatus of producing a tirein the production method of the tire according to the invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[Process and Apparatus for Producing an Uncured Rubber Member]

The process and apparatus for producing the uncured rubber memberaccording to the invention will be described in detail below.Heretofore, the uncured rubber composition contains a reinforcing agent,a softening agent, an activator, an antioxidant, a work-improving agent,a vulcanizing agent and a vulcanization accelerator in addition to astarting rubber. After the uncured rubber composition is shaped into adesired form, or after the uncured rubber composition after the shapingis stuck on a reinforcing material such as cords or the like to form anuncured rubber member, the uncured rubber composition is vulcanized byheating to form a member having a sufficient strength. Therefore, ifheat is applied to the uncured rubber composition by friction or thelike at, for example, a shaping step before the vulcanization step,since the composition contains the vulcanizing agent and vulcanizationaccelerator, there is a possibility of causing the unanticipatedscorching.

On the contrary, in the production process of the uncured rubber memberaccording to the invention are separately prepared a rubber compositionA obtained by excluding the vulcanizing agent from the aboveconventional compounding system and a rubber composition B obtained byexcluding the vulcanization accelerator from the above conventionalcompounding system. Therefore, the rubber composition A and the rubbercomposition B do not contain either the vulcanizing agent or thevulcanization accelerator, respectively, so that the scorching is notcaused at the shaping step even if heat is generated by friction.

In the production process of the uncured rubber member according to theinvention, SBR, NR, BR, butyl rubber and the like are mentioned as astarting rubber used in the rubber composition. These starting rubbersmay be used alone or in a blend of two or more. As the reinforcing agentare mentioned carbon black, silica and the like. As the vulcanizingagent, vulcanization accelerator and other additives, use may be made ofany substances usually used in a rubber industry. Since thiurams amongthe vulcanization accelerators are vulcanizable alone, however, they areexcluded from the application to the rubber compositions A and B.

When the uncured rubber member is produced by using the rubbercomposition of the aforementioned conventional compounding system, oncethe scorching is caused in the shaping machine, there are problems thatthe shaping machine should be disassembled to clean up the inside of themachine but also the scorching may be a cause on the trouble of themachine. On the contrary, according to the invention, there are providedplural shaping machines, and rubber compositions each being notvulcanizable, i.e. a rubber composition A of a compounding systemexcluding a vulcanizing agent and a rubber composition B of acompounding system excluding a vulcanization accelerator are separatelyfed to the shaping machine and extruded therefrom, so that even if heatis generated by friction in the shaping machine, the occurrence of thescorching can be avoided, and hence the conventional problems such asdisassembling and cleaning of the machine due to the occurrence of thescorching and troubles of the machine can be solved.

In the production method of the uncured rubber member according to theinvention, the occurrence of the scorching can be prevented as mentionedabove, so that it is possible to shape these rubber compositions A and Bfrom the plural shaping machines at extrusion rates sufficient to theirmachine capacities and the production efficiency in the shaping can belargely improved. Also, it is not required to take means for decreasingthe compounding amounts of the vulcanizing agent and the vulcanizationaccelerator, so that there is not caused a problem of taking a longvulcanization time.

In the production method of the uncured rubber member according to theinvention, the rubber composition A and the rubber composition B areshaped separately and wound on the support, so that the thus shapeduncured rubber members are rendered into a rubber composition curable inthe subsequent vulcanization step. Therefore, it is possible tovulcanize both the rubber compositions as the thermal diffusion of thevulcanizing agent/vulcanization accelerator is produced by heating atthe vulcanization step.

In order to conduct the sufficient thermal diffusion, it is preferablethat each of the rubber compositions A and B contains an amount of thevulcanizing agent or the vulcanization accelerator sufficient tocompensate for its primary compounding. Particularly, it is preferablethat the rubber composition A contains a double amount of thevulcanization accelerator, while the rubber composition B contains adouble amount of the vulcanizing agent.

Considering the thermal diffusion distance of the vulcanizingagent/vulcanization accelerator, the thickness of the shaped body ofeach rubber composition is preferable to be not more than 2 mm. Andalso, it is difficult to completely overlap these rubber compositionswith each other in the winding, but the overlapping shift is preferableto be not more than 2 mm because there is no problem unless the aboveshift is within a range of conducting the thermal diffusion of thevulcanizing agent/vulcanization accelerator.

Since the crosslinkable rubber compositions are formed by the thermaldiffusion of the vulcanizing agent/vulcanization accelerator at thevulcanization step in the production method of the uncured rubber memberaccording to the invention, if the shaped bodies of the two rubbercompositions are contacted at a fairly higher temperature state justafter the extrusion through the shaping machine, the thermal diffusionof the vulcanizing agent/vulcanization accelerator is caused and hencethere is a fear of starting vulcanization (crosslinking). For this end,it is preferable that the shaped body of the rubber composition israpidly cooled to about 90° C., preferably not higher than 70° C. beforethe winding of the shaped body onto the support.

In the production method of the uncured rubber member according to theinvention, after the rubber compositions are extruded and shaped throughthe shaping machine such as an extruder or the like, the shaped bodiesof these rubber compositions are wound on the support. In this case, theform of the rubber composition after the shaping is not particularlyrestricted unless it can be made into the desired form, and may be anyone of sheet, ribbon, string and the like.

As the winding method, the helical winding is preferable, but is notlimited in accordance with the form of the shaped body. For example,there are helical winding of flat-shaped laminate as shown in FIG. 1(a),helical slant winding as shown in FIG. 1(b), helical winding of aribbon-shaped body on a sheet-shaped body as shown in FIG. 1(c), helicalwinding of shaped bodies laminated vertically to an outer peripheralface of the support, and the like.

As the shaping machine used for extruding the rubber composition in theproduction method of the uncured rubber member according to theinvention, mention may be made of an extruder and the like. By usingplural shaping machines can be separately wound the rubber composition Aand the rubber composition B on the support.

In the production method of the uncured rubber member according to theinvention, the existing ratio of the rubber compositions A and B in theuncured rubber member made of these rubber compositions can be properlychanged in the uncured rubber member. As the changing method, there area method of changing a thickness ratio of the shaped bodies of therubber compositions A and B, a method of changing the winding number ofeither shaped body and the like.

Further, in the production method of the uncured rubber member accordingto the invention, the existing ratio of the rubber compositions A and Bin the uncured rubber member can be properly changed viewing from thewidthwise direction of the support. Such a changing can be realized, forexample, by properly forming a dense portion of the rubber composition Aor B and a loose portion of the rubber composition A or B as shown inFIG. 1(d).

Next, an embodiment of the apparatus for producing the uncured rubbermember according to the invention is explained in detail with referenceto FIG. 2. In FIG. 2, a support 1 is attached to a shaft rotatingthrough the driving of a rotation driving source omitted inillustration. The support 1 is a shaping drum, a last-off shaped bodymade by winding a part of uncured rubber members, cords coated with anuncured rubber and the like on the shaping drum, a base tire forretreading or the like.

The apparatus according to the invention is provided with pluralextruders, two extruders 2 a, 2 b in the embodiment of FIG. 2. Therubber composition A is extruded through the extruder 2 a and the rubbercomposition B is extruded through the extruder 2 b, and the shapedbodies A and B thereof are wound on the support 1.

In this case, if the two shaped bodies A and B of the rubbercompositions contact with each other at a fairly higher temperaturestate just after the extrusion as previously mentioned, there is a fearthat the thermal diffusion of vulcanizing agent/vulcanizationaccelerator is caused to start the vulcanization, so that it ispreferable to provide cooling devices 3 a and 3 b for rapidly coolingthe shaped bodies A and B of the rubber compositions extruded throughthe extruders to about 90° C., preferably not higher than 70° C. beforethe winding of these shaped bodies on the support 1. The cooling devices3 a and 3 b are disposed between the extruders 2 a and 2 b and thesupport 1.

[Tire and Production Method Thereof]

The tire and the production method thereof according to the inventionare described in detail below. In the tire provided with an innerlineraccording to the invention, the rubber component of the innerlinercontains a diene rubber of at least 10% by mass, preferably 10-40% bymass, more preferably 10-35% by mass at a region corresponding to a tireside portion. Therefore, the innerliner becomes higher in the adhesionforce to the side portion mainly composed of a diene rubber as comparedwith the conventional innerliner comprising only a butyl rubber or ahalogenated butyl rubber as the rubber component. In the tire accordingto the invention, air or an inert gas such as nitrogen or the like ismentioned as a gas to be filled in the tire.

On the other hand, the rubber component of the innerliner at a regioncorresponding to a tire tread portion is low in the ratio of dienerubber as compared with the side portion corresponding region. Since thetread portion corresponding region is not so subjected to bending evenin the running at a run-flat state, the internal pressure holdingproperty inherent to the innerliner itself can be enhanced by applying arubber component having the ratio of diene rubber lower than that of theside portion corresponding region (rubber component having a higherratio of butyl rubber or halogenated butyl rubber).

Also, the innerliner in the tire according to the invention ispreferable to be composed mainly of a halogenated butyl rubber and tocontain 90-60% by mass of the halogenated butyl rubber and 10-40% bymass of the diene rubber from a viewpoint of establishing the durabilityand the internal pressure holding property at the run-flat state.

As the diene rubber used in the innerliner are mentioned natural rubberand synthetic diene rubbers, and among them natural rubber ispreferable. As the halogenated butyl rubber are a brominated butylrubber and the like. The innerliner may be compounded with compoundingagents and the like usually used in the innerliner composition in thetire industry in addition to the above diene rubber and halogenatedbutyl rubber.

Preferably, the tire according to the invention is a run-flat tire. Therun-flat tire according to the invention is characterized by disposing areinforcing rubber of substantially a crescent-shaped form at itssection between the innerliner and the carcass ply in the tire sideportion.

In the innerliner of the tire according to the invention, it ispreferable that the ratio of diene rubber in the component for theinnerliner is continuously changed from the side portion correspondingregion to the tread portion corresponding region. Also, the thickness ofthe innerliner may be continuously changed from the side portioncorresponding region to the tread portion corresponding region. In theinnerliner, the high ratio of butyl rubber or halogenated butyl rubberand the large thickness improve the internal pressure holding property,but become disadvantageous in the cost. However, when the rubbercomponent/thickness in the innerliner are continuously changed in thewidthwise direction of the tire, it is possible to attain an optimumarrangement of the rubber component in view of performances/cost.

In the conventional drum shaping, it is considered that it is at leastpossible to obtain the innerliner of the above construction by using adivision body consisting of rubber component compositions for theregions corresponding to the side portion and the tread portion in theapplication of the innerliner. However, the drum shaping is required totake a manual operation as pointed out from the old time, so that thelarge improvement of the shaping efficiency can not be attained and alsothere is a problem of lowering the application accuracy. On thecontrary, the problems in such a drum shaping can be solved by adoptingthe production method of the tire according to the invention.

In the production method of the tire according to the invention, two ormore different rubber compositions are separately taken out from pluralstorage tanks including these rubber compositions and kneaded andextruded through an extruder and then the extrudate is wound on arotating support to form an innerliner for the tire, in which take-outamounts of these rubber compositions are changed so that a rubbercomponent in the innerliner contains at least 10% by mass of a dienerubber in a portion corresponding to a side portion of the tire and aratio of the diene rubber is lower in a portion corresponding to a treadportion of the tire than that in the portion corresponding to the sideportion.

In this case, the ratio of diene rubber in the same innerliner can becontinuously changed by continuously changing the take-out amounts ofdifferent rubber compositions taken out from the plural storage tanks.For instance, the ratio of diene rubber in the rubber component for theinnerliner can be continuously changed from the side portioncorresponding region to the tread portion corresponding region.

When the production method of the tire according to the invention isadopted, it is easy to optionally change the ratio of diene rubberbetween the side portion corresponding region and the tread portioncorresponding region in the innerliner, and the manual operation is notrequired, so that the productivity can be increased. Also, it is easilypossible to optionally change the thickness by the production method ofthe tire according to the invention.

Next, an embodiment of the invention is explained in detail withreference to FIG. 3. In FIG. 3 is shown an outline side view of aproduction apparatus attaining the production method of the tireaccording to the invention. In FIG. 3, a support 4 is attached to ashaft 4 a rotating through the driving of a rotation driving sourceomitted in its illustration. The support 4 is a rigid core for shaping agreen tire. Moreover, the rigid core for shaping the green tire has anouter face form substantially corresponding to an inner face form of aproduct tire. The support 4 has a winding face of a rubber member on itssurface.

An extruder 5 is arranged so as to locate a rubber member feeding port 5a of the extruder 5 in the vicinity of the surface of the support 4.Moreover, the production apparatus shown in FIG. 3 is a combinedapparatus of the support 4 and the extruder 5. The feeding port 5 aincludes both a case providing a usual extrusion orifice and a case thata pair of up and down roller dies is provided instead of the extrusionorifice. As a form of a rubber member extruded from the feeding port 5 aare mentioned a ribbon, a string and the like.

The extruder 5 is provided with two or more storage tanks, two storagetanks 6 x, 6 y in the illustrated embodiment separately storing uncuredrubber compositions X and Y. Also, the storage tanks 6 x, 6 y areprovided with a rubber composition feeding device 7 separately adjustingthe feeding amounts of the rubber compositions X and Y. The rubbercompositions X and Y passed through the rubber composition feedingdevice 7 are charged into a main body of the extruder 5 through a hopperor a feeder 8.

In the production method of the tire according to the invention, therubber compositions having different ratios of diene rubber andhalogenated butyl rubber, for example, rubber composition X containing100% by mass of halogenated butyl rubber as a rubber component andrubber composition Y containing 75% by mass of halogenated butyl rubberand 25% by mass of diene rubber as a rubber component are separatelycharged into the storage tanks 6 x and 6 y, and the feeding amount ofeach rubber composition is controlled by the rubber composition feedingdevice 7 in accordance with the regions of the innerliner to beproduced. The extruder of the illustrated embodiment is provided withthe two storage tanks, but the number of the storage tanks is notlimited thereto and the object of the invention can be achieved unlessthe number of the storage tanks is two or more.

Further, the extruder 5 is provided with a control means controlling thecharging time, charging stop time and flowing amount of each rubbercomposition through the rubber composition feeding device 7 inaccordance with the exchange of the support or the regions of theinnerliner to be produced. Thus, the rubber composition used can bechanged, for example, in the tread portion corresponding region and theside portion corresponding region of the innerliner. Further, the ratioof diene rubber can be continuously changed from the side portioncorresponding region to the tread portion corresponding region bycontinuously changing the take-out amount of each rubber composition inthe formation of the one innerliner.

And also, the extruder 5 is provided with a linear moving mechanism 9.The linear moving mechanism 9 linearly moves the extruder 5 along acentral axis R of a rotating shaft 4 a of the support 4. This movementis to successively wind the rubber member fed from the feeding port 5 aonto the winding face of the support in a helical form. On the otherhand, the support 4 may be provided with a linear moving mechanism (notshown) instead of the linear moving mechanism 9.

Furthermore, when the winding face of the support 4 is a curved facehaving a large curvature, the extruder 5 is provided with a pivot movingmechanism (not shown) in addition to the linear moving mechanism 9. Thepivot moving mechanism turns the top of the feeding port 5 a along thewinding curved face of the support 4.

Moreover, the production apparatus shown in FIG. 3 has a guide roller 10ahead of the feeding port 5 a of the extruder 5. The guide roller 10guides the rubber member fed from the feeding port 5 a to a givenposition of the winding face of the rotating support 4.

The following examples are given in illustration of the invention andare not intended as limitations thereof.

EXAMPLE 1

A rubber composition A excluding a vulcanizing agent and a rubbercomposition B excluding a vulcanization accelerator are preparedaccording to a compounding recipe shown in Table 1. Then, the rubbercomposition A and the rubber composition B are separately extrudedthrough extruders 2 a and 2 b in the apparatus shown in FIG. 2 and woundon a rotating support 1 to form uncured rubber members.

COMPARATIVE EXAMPLE 1

The conventional rubber composition C is prepared according to thecompounding recipe of Table 1. Then, it is extruded through a singleextruder and wound on the rotating support 1 to form an uncured rubbermember. TABLE 1 (parts by weight) Rubber Rubber Rubber composition Acomposition B composition C SBR#1500 *1 100 100 100 Carbon black (ISAF)50 50 50 Process oil 10 10 10 Zinc oxide 5 5 5 TBBS (vulcanization 2 0 1accelerator) *2 MBTS (vulcanization 1 0 0.5 accelerator) *3 Sulfur 0 4 2Total 168.0 169.0 168.5Note:*1 trade mark of styrene-butadiene rubber, made by JSR Corporation*2 N-(t-butyl)-2-benzothiazole sulfenamide*3 dibenzothazyl disulfide

In Example 1 is not observed the scorching at the shaping step of eachrubber composition, while the scorching is observed at the shaping stepof the rubber composition in Comparative Example 1. As a result, it isconfirmed that the occurrence of the scorching can be prevented by theproduction method and production apparatus according to the invention.

COMPARATIVE EXAMPLES 2-3, AND EXAMPLES 2-4

Rubber compositions X, Y, Z, W are prepared according to compoundingrecipes shown in Table 2, respectively, and used in a regioncorresponding to a tread portion or a side portion of a tire at acombination shown in Table 3 to produce an innerliner, from which isproduced a side-reinforcement type run-flat tire having a tire size ofPSR 245/40ZR18. Moreover, the innerliners of Comparative Examples 2 and3 are produced by the conventional drum shaping with the rubbercomposition X or Z, while the innerliners of Examples 2-4 are producedby the apparatus shown in FIG. 3. With respect to these tires, therun-flat durability and air holding property are measured by thefollowing methods to obtain results shown in Table 3.

The run-flat durability is evaluated by measuring a running distanceuntil the occurrence of tire trouble when the test tire is run at aspeed of 90 km/hr under conditions of a load of 6.23 kN and an internalpressure of 0 kPa, and represented by an index on the basis that therunning distance of Comparative example 2 is 100. The larger the indexvalue, the better the run-flat durability.

The air holding property is evaluated by measuring an internal tirepressure after the test tire inflated under an internal pressure of 230kPa is left to stand at a temperature of a test chamber of 25±2° C. for30 days, and represented by an index on the basis that the internalpressure holding ratio of Comparative example 2 is 100. The larger theindex value, the better the air holding property. TABLE 2 (parts byweight) Rubber Rubber Rubber Rubber composition composition compositioncomposition X Y Z W Natural rubber 0 10 20 30 Brominated 100 90 80 70butyl rubber Carbon black 50 50 50 50 (N660) Process oil 10 10 10 10Zinc white 3 3 3 3 Stearic acid 2 2 2 2 Sulfur 1 1 1 1

TABLE 3 Com- Com- parative parative Exam- Exam- Exam- Exam- Exam- ple 2ple 3 ple 2 ple 3 ple 4 Rubber composition X Z X Y Y in tread portioncorresponding region Gauge of tread portion 1.0 1.0 1.0 1.0 1.0 (mm)Rubber composition X Z Z W W in side portion corresponding region Gaugeof side portion 1.0 1.0 1.0 1.0 1.3 (mm) Run-flat durability 100 125 125140 140 Air holding property 100 90 95 90 95

In Comparative Example 3, the diene rubber is mixed with the brominatedbutyl rubber in order to improve the run-flat durability of ComparativeExample 2 corresponding to the conventional innerliner. Due to themixing of the diene rubber, the air holding property largely lowersthough the run-flat durability is improved.

Example 2 is a case that the diene rubber is compounded in only the sideportion corresponding region as compared with Comparative Example 2. Inthis case, the run-flat durability is improved by the mixing of thediene rubber in the side portion corresponding region, while thelowering of the air holding property is slight because the rubbercomponent in the tread portion corresponding region consists of only thebrominated butyl rubber likewise Comparative Example 2.

Example 3 is a case that the ratios of diene rubber in the side portioncorresponding region and the tread portion corresponding region are madehigher than those of Example 2. The air holding property is equal tothat of Comparative example 3, while the run-flat durability is furtherimproved as compared with those of Comparative Example 3 and Example 2.

Example 4 is a case that the gauge of the side portion correspondingregion is made 1.3 times larger than that of Example 3. In this case,the run-flat durability is very excellent likewise Example 3, while theair holding property is improved by thickening the side portioncorresponding region. Also, the lowering of the air holding property isslight as compared with Comparative Example 2.

INDUSTRIAL APPLICABILITY

In the production method of the uncured rubber member according to theinvention, the uncured rubber composition to be shaped in the shapingmachine is made of a compounding system excluding either the vulcanizingagent or vulcanization accelerator, so that the occurrence of thescorching resulted from heat generation due to the friction in theshaping can be prevented and the production efficiency in the shapingcan be largely increased.

On the other hand, when the innerliner, characterized in that the rubbercomponent for the innerliner contains at least 10% by mass of dienerubber in the region corresponding to the tire side portion and theratio of diene rubber in the region corresponding to the tire treadportion is made lower than that in the side portion correspondingregion, is applied to the tire, the run-flat durability can be largelyimproved while suppressing the lowering of the air holding property ascompared with the tire using the conventional innerliner composed ofonly butyl rubber or halogenated butyl rubber.

Also, by adopting the production method of the tire according to theinvention, characterized in that when the rubber compositions areseparately taken out from plural storage tanks having different rubbercompositions and kneaded and extruded through the extruder and theextrudate is wound on the rotating support to form an innerliner layerfor the tire, the take-out amounts of the rubber compositions arechanged so that the rubber component for the innerliner contains atleast 10% by mass of diene rubber in the region corresponding to thetire side portion and the ratio of diene rubber in the regioncorresponding to the tire tread portion is made lower than that in theside portion corresponding region, it is easy to optionally change theratio of diene rubber in the regions of the innerliner corresponding tothe side portion and the tread portion and the manual operation is notrequired and hence the productivity is increased.

1. A method of producing an uncured rubber member, characterized in thata rubber composition A of a compounding system excluding a vulcanizingagent and a rubber composition B of a compounding system excluding avulcanization accelerator are produced separately, and the rubbercomposition A and the rubber composition B are shaped into given formsthrough a shaping machine, respectively, and wound on a rotatingsupport.
 2. A method of producing an uncured rubber member according toclaim 1, wherein the shaping machine is an extruder.
 3. A method ofproducing an uncured rubber member according to claim 1, wherein theform of the rubber composition A and/or B after the shaping is any oneof sheet, ribbon and string.
 4. A method of producing an uncured rubbermember according to claim 1, wherein the rubber composition A and/or Bafter the shaping is wound in a helical form.
 5. A method of producingan uncured rubber member according to claim 1, wherein the rubbercomposition A and/or B after the shaping is cooled before the winding onthe rotating support.
 6. A method of producing an uncured rubber memberaccording to claim 1, wherein an existing ratio of the rubbercomposition A and the rubber composition B in the uncured rubber memberis properly changed.
 7. A method of producing an uncured rubber memberaccording to claim 1, wherein an existing ratio of the rubbercomposition A and the rubber composition B in the uncured rubber memberis properly changed in a widthwise direction of the support.
 8. Anapparatus for producing an uncured rubber member, comprising a rotatingsupport and plural extruders connecting to the support.
 9. An apparatusfor producing an uncured rubber member according to claim 8, wherein acooling device is arranged between the extruder and the support.
 10. Atire provided with an innerliner, characterized in that a rubbercomponent for the innerliner contains at least 10% by mass of dienerubber in a region corresponding to a tire side portion and a ratio ofdiene rubber in a region corresponding to a tire tread portion is madelower than that in a side portion corresponding region.
 11. A tireaccording to claim 10, wherein the rubber component for the inner-linercontains 10-40% by mass of diene rubber in the region corresponding tothe side portion.
 12. A tire according to claim 10, wherein the rubbercomponent for the innerliner is composed mainly of halogenated butylrubber and contains 90-60% by mass of halogenated butyl rubber and10-40% by mass of diene rubber.
 13. A tire according to claim 10,wherein the diene rubber is a natural rubber.
 14. A tire according toclaim 10, wherein a reinforcing rubber of substantially acrescent-shaped form in section is arranged an innerliner and a carcassply in the tire side portion.
 15. A tire according to claim 10, whereina ratio of diene rubber in the rubber component for the innerliner iscontinuously changed from the side portion corresponding region to thetread portion corresponding region.
 16. A method of producing a tireprovided with an innerliner by separately taking out rubber compositionsfrom plural storage tanks containing different rubber compositions andkneading and extruding through an extruder and winding the resultingextrudate on a rotating support to form an innerliner layer,characterized in that take-out amounts of the rubber compositions arechanged so that a rubber component for the innerliner contains at least10% by mass of diene rubber in a region corresponding to a tire sideportion and a ratio of diene rubber in a region corresponding to a tiretread portion is made lower than that in a side portion correspondingregion.
 17. A method of producing a tire according to claim 16, whereinthe take-out amount is continuously changed.
 18. A method of producing atire according to claim 16, wherein the rotating support is a rigid corehaving an outer surface form substantially corresponding to an innersurface form of a product tire.